1. Field of the Invention
The invention concerns an operator panel for film extrusion plants.
2. Description of the Prior Art
Flat film and blown film extrusion plants are known sufficiently. Such a plant is illustrated in e.g. EP 0 873 846. Usually these plants are controlled by an operating panel. These operating panels usually contain at least the following functional elements:                an input terminal at which functional parameters of the film extrusion plants can be set.        An indicator device on which the extrusion plant and the associated extruders and likewise their operating parameters are displayed.        
The operating panels are mounted at an accessible part in the immediate surroundings of the extruder. The operating panel is surrounded by extruders particularly in blown film extrusion plants where the extruders are arranged all around the extrusion plant.
The extrusion plant is usually displayed as a sketch. However in known equipment the display conforms not to the actual arrangement of the extruders around the extrusion nozzle, but instead, the display is in accordance with other standpoints. Most frequently one comes across an arrangement of the extruders according to their numbering. Here the extruders are sketched as if are they arranged in a line.
However it is common to all known display types that the extruders are not arranged according to their actual arrangement around the extrusion nozzle and/or the blowing head. This factor leads to difficulties particularly in the case of blown film extrusion plants.
Machine operators who sit at an operating panel of the extrusion plant wherein the operating panel is adjoining the blowing head or—in the case of flat film extrusion—adjoining the nozzle, do not know whether the extruders are displayed on the operating panel in the correct order or whether they are laterally reversed. For these reasons the machine operators must repeatedly ascertain the numbers of the individual extruders.